Metacognition in prospective memory: are performance predictions accurate?

This study investigated the role of metacognition in event-based prospective memory. The aim of the study was to explore the relation between an item-level prediction (judgments of learning, JOL) and actual performance. The task and JOLs allowed a differentiation of the two components of prospective memory tasks (retrospective vs. prospective). Results revealed that individuals' predictions were (moderately) accurate for delayed JOLs but not for JOLs that had to be given immediately after task encoding. Moreover, data revealed an underconfidence-with-practice effect only for the retrospective component. For the prospective component, a substantial and general level of underconfidence in individuals' prediction-performance ratios was observed. The importance of metacognitive factors for prospective memory is discussed.

Associative recognition memory for faces: more pronounced age-related impairments in binding intra- than inter-item associations.

Performance in recognition memory for associations between arbitrarily paired items is substantially disrupted in old age. The present study examined whether older adults show more or less of a deficit when the to-be-associated items can be 'unitized' into a single representation during encoding. Results revealed that older adults are disproportionately impaired in their memory for unitizable face-pairs, suggesting substantial age deficits in unitization processes required for the formation of associations between highly overlapping stimuli. Potential compensatory mechanisms are discussed that may account for these preliminary results of a selective age deficit in the encoding or retrieval of intra-item associations.

Hippocampal lesion patterns in acute posterior cerebral artery stroke: clinical and MRI findings.

BACKGROUND AND PURPOSE: Reports of ischemic stroke affecting the hippocampus are rare. In this study we used diffusion-weighted MRI (DWI) to characterize patients with posterior circulation stroke involving the hippocampus. METHODS: Fifty-seven consecutive acute stroke patients with hippocampal infarct (HI) on DWI were analyzed with regard to clinical features and ischemic lesion patterns. The last 20 of these underwent additional neuropsychological testing of short-term, working, and episodic long-term memory. RESULTS: We found unilateral HI in 54 and bilateral HI in 3 patients. Visual analysis identified 4 patterns of DWI lesion affecting (1) the complete hippocampus (15/60), (2) the lateral (19/60) or (3) dorsal (22/60) parts of the hippocampal body and tail, and (4) circumscribed lesions in the lateral hippocampus (4/60), corresponding well to hippocampal vascular anatomy. In all cases DWI showed further ischemic lesions in the posterior circulation. Symptoms from lesions outside the hippocampus were the common leading clinical signs. Whereas mnestic deficits were prominent in only 11/57 patients, neuropsychological examination in 20 patients showed deficits of verbal episodic long-term memory in left and of nonverbal episodic long-term memory in right HI. CONCLUSIONS: Several phenotypic lesion patterns can be distinguished in HI that usually occur as part of multifocal PCA ischemia. A careful neuropsychological examination is necessary to detect resulting memory deficits.

Selective disruption of hippocampus-mediated recognition memory processes after episodes of transient global amnesia.

Transient global amnesia (TGA) is characterized by the abrupt onset of severe amnesia without concomitant focal neurological symptoms. Recent studies revealed that small and punctate MR-signal diffusion-weighted imaging (DWI) lesions can be found within the hippocampus of TGA patients during the post-acute phase. On the basis of dual-process models of recognition memory, the present study examined the hypothesis that hippocampal dysfunction as suggested by these DWI lesions disrupts hippocampus-mediated recollection in patients with TGA, whereas familiarity-based recognition memory that is assumed to be supported by extra-hippocampal brain regions should be unaffected. We administered a recognition memory task for faces and words to eleven TGA patients during the post-acute phase and to eleven matched controls. Receiver operating characteristics (ROCs) were obtained in order to derive estimates of familiarity and recollection by applying a formal dual-process model of recognition memory. Analyses of ROC curves revealed a disruption of recollection in TGA patients' memory for words [t(20)=2.70, p<.05], but no difference in familiarity-based recognition memory between patients and controls [t(20)=-1.10, p=.284]. Post hoc analyses indicated that the deficit in recollection is more pronounced in TGA patients who show visible hippocampal lesions on diffusion-weighted MR imaging compared to those without detectable hippocampal lesions. In conclusion, consistent with recent neuroanatomical dual-process models of recognition memory, hippocampal dysfunction in patients with TGA is associated with a selective effect on specific recognition memory subprocesses.

The transience and nature of cognitive impairments in transient global amnesia: a meta-analysis.

Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of severe amnesia without concomitant focal neurological symptoms. This meta-analysis of the cognitive characteristics of TGA addressed two main issues. First, we examined the hypothesis that the acute phase of TGA is associated with changes of anterograde and retrograde episodic long-term memory sparing semantic and short-term memory, while we had no clear prediction for potential reductions of executive functions due to the relative lack of previous studies addressing this issue. Second, we analyzed the time-course of changes in cognitive functions throughout three time intervals--acute (0-24 hours after TGA onset), postacute (24 hours to 5 days), and long-term phase (5-30 days)--to reveal whether there is a fast versus a delayed recovery. The results of the meta-analysis on 152 effect sizes from 25 studies showed that TGA is characterized by an extraordinarily large reduction of anterograde (d* = 1.89) and a somewhat milder reduction of retrograde (d* = 1.28) episodic long-term memory. Moreover, our results indicate the existence of additional, nonamnestic cognitive changes during TGA, because executive functions were also diminished (d* = 0.79). Reductions in both anterograde episodic long-term memory and executive function recover slowly, as slightly poorer performance in these cognitive domains can be found in the postacute phase (d*s = 0.32 and 0.44). All cognitive diminutions resolved within the long-term phase, by this calling into question previous reports of poorer performance of TGA patients relative to comparison subjects weeks or months after the attack.

Adult age differences in event-based prospective memory: a meta-analysis on the role of focal versus nonfocal cues.

Studies of age differences in event-based prospective memory indicate wide variation in the magnitude of age effects. One explanation derived from the multiprocess framework proposes that age differences depend on whether the cue to carry out a prospective intention is focal to ongoing task processing. A meta-analysis of 117 effect sizes from 4,709 participants provided evidence for this view, as age effects were greater when the prospective cue to the ongoing task was nonfocal compared with when it was focal. However, the results only support a weaker but not a stronger prediction of the multiprocess framework, as age impairments were reliably above zero for both types of retrieval cues.

Complex prospective memory: development across the lifespan and the role of task interruption.

Prospective memory (PM) reflects the product of cognitive processes associated with the formation, retention, delayed initiation, and execution of intentions. It has been proposed that developmental changes in PM across the lifespan are heavily dependent upon the developmental trajectory of executive control functions. This study is the first to apply a complex PM task to children, young adults, and older adults. The procedure allows for the assessment of each of the 4 phases of PM. During intention execution, the authors additionally manipulated whether participants had to actively interrupt attention to the current 'ongoing' task in order to switch to the execution of the next intended task. Group differences mirroring inverted U-shaped functions were observed in those phases conceptualized as relying on executive control (intention formation, initiation, and execution). Age differences in intention execution were substantially greater when active task interruption was necessary. The current study provides the first evidence of growth and decline of complex PM across the lifespan and suggests that the degree of inhibitory control needed to succeed in the task may be one factor underlying this development.

Time-based and event-based prospective memory across adulthood: underlying mechanisms and differential costs on the ongoing task.

The authors investigated the phenomenon that performance in an ongoing task declines when individuals must carry out a prospective memory (PM) task. This effect is referred to as the PM interference effect. The authors examined whether the PM interference effect differs between event-based and time-based PM tasks and whether it is increased among the elderly. The authors also investigated adult age differences in PM performance and the potential underlying mechanisms of the age deficits in PM. They found that the PM interference effect was greater in event-based than in time-based tasks. However, aging was not associated with an increase in PM interference effects. Age differences in PM performance were more exaggerated in time-based than event-based PM, but they were not mediated by age differences in traditional cognitive ability measures. In time-based PM, age showed a unique adverse effect even after controlling for the ability to externally monitor the time, leading to the possibility that aging disrupts time-based PM because of deficits in internally processing the time.

Emotional development across adulthood: differential age-related emotional reactivity and emotion regulation in a negative mood induction procedure.

The present study examines the hypothesis that older adults might differentially react to a negative versus neutral mood induction procedure than younger adults. The rationale for this expectation was derived from Socioemotional Selectivity Theory (SST), which postulates differential salience of emotional information and ability to regulate emotions across adulthood. The present data support a view of differential age-related effects of negative mood inductions with greater and more heterogeneous emotional reactivity among older adults, who showed a substantially greater decrease in self-rated pleasantness, calmness, and wakefulness than younger adults. Moreover, relative to the younger adults, emotion regulation in terms of mood repair was more effective among the older adults. The age-related mood effects are discussed in terms of SST and have practical implications for the study of emotion and cognition across adulthood.

Development and validation of the Cognitive Telephone Screening Instrument (COGTEL) for the assessment of cognitive function across adulthood.

The authors introduce a screening instrument that assesses cognitive-function domains across adulthood over the telephone. The authors administered the Cognitive Telephone Screening Instrument (COGTEL) to 81 younger adults (M = 25.6 years) and 83 older adults (M = 66.9 years). Each participant completed the COGTEL twice, once over the telephone and once in a face-to-face assessment. The authors (a) analyzed the degree of agreement between face-to-face and telephone COGTEL scores, (b) developed a COGTEL Total score that reflects global cognitive functioning, and (c) examined concurrent validity. The method of administration did not largely influence mean levels, rank orders, or factor structure as revealed by confirmatory factor analysis. Moreover, age differences were not modulated by the form of administration. The distribution of COGTEL Total scores followed a Gaussian function, which prevents COGTEL from being limited by ceiling effects. The results provide evidence for the validity and reliability of the COGTEL to assess cognitive functioning in large-scale epidemiological studies, longitudinal studies, and clinical follow-up among healthy adults.

Delayed-execute prospective memory performance: the effects of age and working memory.

This study follows the novel delayed-execute prospective memory paradigm, which involves briefly delaying the execution of an intended action, a task that has been shown to produce substantial age effects. During the ongoing task, sentences were presented, and participants had to answer reading-comprehension questions and general knowledge questions. In the prospective memory task, the participant was to press a key after the presentation of a specific cue in the sentences-but not before a subsequent phase of the ongoing task was reached. In contrast to previous studies using older participants taken from very broadly defined age ranges, this study examines development of delayed-execute prospective memory more precisely by examining a total of 4 age groups: a younger age group (age range = 22-31; n = 27), a young-old age group (age range = 60-69; n = 34), a middle-old age group (age range = 70-79; n = 31), and an old-old age group (age range = 80-91; n = 35). This study investigates the dependence of (age-related) delayed-execute prospective memory performance on working memory capacity by disrupting the phonological loop during the delay period as well as its dependence on neuropsychological processes such as inhibitory control and processing speed. The results show that (a) delayed-execute prospective memory particularly declines within the group of older participants, (b) delayed-execute prospective memory is diminished when working memory load is high during the delay period, and (c) age-related performance in delayed-execute prospective memory may be mediated by inhibitory control. The findings are discussed in the context of the frontal lobe hypothesis of cognitive aging.

Intra- and inter-item associations doubly dissociate the electrophysiological correlates of familiarity and recollection.

Single-process models of recognition memory posit that recognizing is based on a unidimensional value of global memory strength. By contrast, dual-process models propose the existence of two independent processes subserving the explicit recognition of previously encountered episodes, namely "familiarity" and "recollection." Familiarity represents a noncontextual form of recognition that may only support the retrieval of associative information when the to-be-associated information can be unitized, such as when two photographs depicting the same person are memorized (intra-item associations). Conversely, recollection enables retrieving associations between arbitrarily linked information, such as associations between photographs of different persons (inter-item associations). By measuring event-related brain potentials (ERPs), we obtained a double dissociation of familiarity and recollection that strongly favors dual-process accounts of recognition memory: the electrophysiological correlate of familiarity was significantly larger for intra- than for inter-item associations. Conversely, the electrophysiological correlate of recollection was significantly larger for inter- than for intra-item associations.